Problem with beagle thunderbird plugin

Dear All,
 I have tried to install the beagle plugin for thunderbird 0.1.3 on
thunderbird 2.0.0.21 - the OS environment is Ubuntu Jaunty.
Unfortunately, no email is indexed, I only get the error:

An error occured while indexing. Error description: TypoError:
account.incomingServer has no properties

(this I can see when clicking on the beagle logo with the alert sign
in the thunderbird status bar area.)

Can anyone please tell me how I might be able to fix it. I have two
IMAP accounts defined, one work and one private.

Thanks a lot,
Regards,